Product Description The Rosco Manufacturing ROS-BCG-002 Bolt Carrier Group is a complete, mil-spec BCG engineered for AR-15 rifles chambered in 5.56 NATO, .223 Remington, and .300 AAC Blackout. Featuring a tough Black Phosphate finish, a chrome-lined gas key and bolt channel, and a properly staked gas key fastened with Grade 8 hardware, this BCG is built to perform under the most demanding conditions. The carrier is machined from 8620 steel while the bolt is manufactured from C158 steel and subjected to both magnetic particle inspection (MPI) and high-pressure testing (HPT), ensuring every unit meets rigorous quality standards. Full-Auto rated and shot-peened throughout, this BCG delivers consistent lockup and reliable function whether you are a civilian shooter or a military end user. Rosco Manufacturing balances direct input from military users and everyday carbine shooters to produce components that exceed expectations every time. Product Highlights Full-Auto rated complete Bolt Carrier Group compatible with 5.56 NATO, .223 Remington, and .300 AAC Blackout AR-15 platforms 8620 steel carrier with durable Black Phosphate coating and chrome-lined gas key and bolt channel for long-term performance Gas key manufactured from 4130 steel, attached with Grade 8 hardware, and properly staked to mil-spec standards C158 steel bolt is shot-peened, MPI/HPT tested, and matched to the barrel for consistent accuracy and dependable lockup Hard chrome coated mil-spec firing pin, hardened 4340 steel cam pin, and upgraded extractor for maximum reliability Specs Brand: Rosco Manufacturing MPN: ROS-BCG-002 UPC: 181969500838 Caliber: 5.56 NATO, .223 Remington, .300 AAC Blackout Finish: Black Phosphate Carrier Material: 8620 Steel Gas Key: 4130 Steel, Attached with Grade 8 Hardware, Properly Staked Cam Pin: Hardened 4340 Steel Firing Pin: 8740 Steel, Heat-Treated, Mil-Spec, Centerless Ground, Hard Chrome Coated Bolt Material: C158 Steel, Phosphate Coated, MPI/HPT Tested Extractor: 4140 Steel, Heat Treated, Shot Peened Ejector: S2-S7 Tool Steel, Shot Peened Rating: Full-Auto Rated Country of Origin: USA Compatible With: AR-15 Upper Receivers and Rifles chambered in 5.56/.223/.300 BLK Disclaimer: We strive to provide accurate and up-to-date product descriptions, specifications, and images; however, errors or omissions may occasionally occur. We are not responsible for any inaccuracies or discrepancies in the content provided. If you notice anything incorrect or unclear, please contact us so we can correct it. When in doubt, we recommend verifying details directly with the product&';s manufacturer.